Multiplying operating mechanism for permeability tuning purposes



June 1 6, 1942. M. J. KIRK ETAL 2,286,283

MULTIPLYING OPERATING MECHANISM FOR PERMEABIL-ITY TUNING PURPOSES FiledFeb. 20, 1939 INVENTORS MflET/IYJ k/EK FREDERICK/V J4 c015.

MMEM

ATTORNEY.

Patented June 16, 1942 MULTIPLYING OPERATING MECHANISM FOR. PERMEABILITYTUNING PURPOSES Martin J. Kirk and Frederick N. Jacob, Chicago, Ill.,assignors to Johnson Laboratories, Inc., Chicago, 111., a corporation ofIllinois Application February 20, 1939, Serial No. 257,312

'6 Claims.

Our invention relates to mechanism for operating the movable elements ofinductors havin variable permeability, to change the inductance of saiddevices for desired purposes, for example for effecting the tuning ofresonant circuits of which said inductors may be parts. Our invention isapplicable particularly to inductors provided with cylindricalferromagnetic cores, in which permeability variation is effected bygiving different positions to the cores relatively to the coils withwhichthey are used, either by moving the cores, the coils, or both.

With inductors of the kind referred to, particularly where theinductance variation is desired to tune resonant circuits over a bandsuch as the broadcast band, it is found in practice desirable to imparta considerable amount of movement to the movable elements of theinductors, which movable elements are generally for convenience taken asthe cores of the inductors rather than the coils, since it is found inpractice that more satisfactory results are S e y using co ls ofrelatively small diam- .eter and substantial length, and cores of thesame proportions rather than coils and cores of large diameter and shortlength. With inductors of the particular type last referred to, it isimportant that the operating mechanism shall impart a straight linemovement to the cores,

to effectively operate them and avoid friction in the operatingmechanism. At the same time, it is desirable to provide the operatingmechanism with parts having rotary movement to facilitateconnection withoperating knobs and to facilitate the use of indicating scales of onekind or another, the operating knobs being preferably related to therest of the operating mechanism so that they have considerably moremovement than other parts of the operating mechanism and also than thecores, so that the adjustment of the cores may be effected with anydegree of precision desired.

By our invention we provide improved mechanism for transforming therotary motion of the operating mechanism into rectilinear motion so thatthe ferromagnetic cores of the inductors may be operated insubstantially an ideal manner.

Our invention will be best understood by reference to the accompanyingdrawing illustrating a preferred embodiment thereof, in which:

Fig. 1 shows our operating mechanism in front elevation;

Fig. 2 shows our operating mechanism and variable inductors operatedthereby in rear elevation;

Fig. 3 is a vertical, sectional view of the structure shown in Figs. 1and 2, taken along the line 3-3 in Fit. 2, and

Fig. 4 is a fragmentary view illustrating a modified form of linkmechanism between the operating shaft and the core carrying member ofthe operating mechanism.

Similar numerals refer to throughout'the several views.

As shown in Fig. 1, our operating mechanism is provided with a mountingplate ll supporting a shaft II for rotary movement, a drum I! beingrigidly secured to said shaft in front of said plate. A rotary spindleI3 is also mounted in the plate It and extends forwardly therefrom forconnection with the drum I! by a cable J4 to drive said drum by rotationof said spindle. As shown in Fig. 3, the spindle II is provided with anoperating knob It for operation by the operator of the device. Thediameter of the spindle I3 is very much less than the diameter of thedrum l2, and in that way the amount of rotation of the spindle I3 ismuch greater than the amount of rotation of the shaft H, whichfacilitates accurate operation of said shaft. As shown in Figs. 1 and 3,the cable I] is continued from the upper portion of the drum in oppositeirections horizontally around grooved sheaves I6 and H, from which saidcables return to a pointer l8 mounted for sliding horizontal engagementon the upper edge of a plate l9 supported by the mounting plate ID infront of the upper part of the drum l2, to carry an similar partsindicating scale 20. The movement of the pointer I8 relative to thescale 20 is thus proportional to the angular movement of the shaft ll.

As shown in Fig. 2, the shaft H has secured to its back end a crank 2|,the outer end of which crank is pivotally connected at 22 with themid-portion of a lever 23, the upper end of which is provided with aroller 14 held in rolling engagement with a fence 25 by a spring 26,said fence being formed fromthe mounting plate II and being horizontallydisposed, assuming that as shown in Fig. 2, vertical movementis to beimparted to the ferromagnetic cores employed. The other end of the lever23 is pivotally connected at 21 with a yoke 28 rigidly secured at itsmid-portion to a bar 29 mounted for sliding engagement in a flange llformed from the mounting plate l0, so that said bar may slidefreelythrough said flange in a vertical direction.

The lower edge of the mounting plate |8 is provided with a flange 3|supporting the lower ends of insulating tubes 32 on which inductancecoils 33 are wound, the upper ends of said tubes being supported by'aplate 34 of insulating material carried by flanges 35 formed from themounting plate I 8. The tubes 32 contain with a sliding fitferromagnetic cores 38 from the upper ends of which slender threadedrods 31 extend for connection with the yoke 28. The rods 31 carrythin-walled insulating sleeves 38 adjacent the yoke-28, which sleevesare preferably of material much softer than the rods 31, for example,fibre, and at first loosely fit the rods 31; said sleeves are pressedfirmly against the yoke 28 by clip plates 39 secured to yoke 28 in anysuitable mannenforexample by rivets 48, said clip plates being resilientso as t exert yielding pressure on the sleeves 38 sufficient to pressthe sleeves more or less into the threads on the slender rods 31, toprevent accidental turning of said rods in said sleeves, as well as tohold said sleeves in fixed position on the yoke 28. This provides aconstruction which insulates the cores 36 from the yoke 28 and at thesame time permits adjustment of the cores relatively to the yoke byturning the rods 31, for any desired purposes, such as aligning andtracking the cores.

We find it desirable to restrict the movement of the crank 2| tosubstantially 90 by stops 4| and 42 formed from the mounting plate In insuch a manner that the movement of the crank 2| is substantially 45above and 45 below a horizontal line through the center of the shaft II,for the direction of movement of the cores 36 illustrated in Fig. 2. Theeffective length of the crank 2| is made equal to the center-tocenterdimension between the pivotal connection 22 and the roller 24, as wellas equal to the center-to-center dimension between the pivotalconnection 22 and the pivotal connection 21, the centers of the pivotalconnections 22, 21 and the center of the roller 24 being insubstantially a straight line. The diameter of the roller 24 is so takenthat the center of the roller is maintained by the fence 25 and thespring 28, in a horizontal line extendingthrough 'the axis of theshaftWith the relation of parts described, angular movement of the crank 2|between the stops 4| and 42 will move the center of the pivotalconnection 21 in a vertical line extending through the axis of the shaftH, and as a result, operation of said crank moves the yoke 28vertically, and thus imparts no lateral movement to the rods 31 and thecores 36.

The lever 23 is provided with a spring 43 en- The coils 33 may beenclosed by a shield 48 if desired, which shield is removed in Fig. 2 tomore clearly show the parts contained therein.

In Fig. 4 we illustrate a modified form of the connecting device of ouroperating mechanism, in which the lever 23 is pivotally connected at itsupper end at 43 with a link 58, extending vertically and pivotallysupported at its upper end at 5| from the mounting plate l8, the'rest ofthe construction being the same as above described in connection withFig. 2. In this case, a spring 52 engages the pivotal connections 49 and5| to take up the lost motion of said connections.

With this construction, the accuracy of movement of thepivotalconnection 21 at the lower end of the lever 23, in a verticalline through the axis of the shaft II, is determined by the length ofthe link 58, the departure of the piv otal connection 21 from saidvertical line of movement being inappreciable where the crank 2| isrestricted to the mid-portion of its movement and the link 58 is ofsubstantial length.

It is to be noted, that if desired inany'case, the angle of movement ofthe crank 2| may be made greater than 90, or said movement may beunequally distributed relatively to a horizontal line through the axisof the shaft or both, without departure of the pivotal connection 21from straight line vertical movement, if the roller and fenceconstruction, 24, 25, of Fig. 2 is employed, for which greater angle ofoperation, however, there may be a slight departure of the pivotalconnection 21 from vertical straight line movement if the linkconnection 58 of Fig. 4 is used, the amount of said departure beingdetermined by the length of the link 58.

While we have shown our invention in the particular embodiment abovedescribed, it will be understood that ,we do, not limit ourselvesthereto as we may employ equivalents thereof without departing from thescope of the appended claims.

Having thus described our invention what we claim is:

1. An operating mechanism for the movable element of a variableinductance device having straight-line movement, consisting of a rotaryshaft, a crank carried by said shaft, a lever pivotally connected at itsmid-portion with and gaging the pivotal connection 22 to take up any alost motion there may be in said connection, and the yoke 28 carries aspring 44 engaging the pivotal connection 21 to take up any lost motionthere may be in that pivotal connection. The lower end of the bar 29 isconnected with a side wall of the mounting plate l8 by a spring 45 whicheliminates lost motion between the bar 28 and the guiding flange 38.. Asshown in Figs. 1 and 3, the mounting plate l8 may be provided on itsfront wall with capacitors 48 .and 41 of the trimmer type, which may beconcarried by said crank, said crank having movement in oppositedirections from a position in alignment with said lever, and meansrestraining movement of one end portion of said lever substantially tothe center line of said alignment, whereby movement of the other endportion of said lever is limited to substantially straight-line movementperpendicular to said center line of alignment and said other endportion of said lever may be mounted for movement inthe line of movementof the movable element of the in- ,ductance device for operativeconnection with said movable element.

2. An operating mechanism for the movable element of a variableinductance device having straight-line movement, consisting of a rotaryshaft, a crank carried by said shaft, a lever pivotally connected at itsmid-portion with and carried by said crank, said crank having movementin opposite directions from a position in alignment with said lever, andmeans restrain- 1 ing movement of one end portion of said lever pacityin operation after they are so aligned.

substantially to the center line of said alignment, whereby movement ofthe other end portion of said lever is limited to substantiallystraight-line movement perpendicular to said 'tion of said lever may bemounted for movement in the line of movement of the movable element ofthe inductance device for operative connection with said movableelement, said restraining means including a member having a planesurface extending in the direction of said center line of alignment andin engagement with the restrained lever end held against and movablealong said plane surface towards and from said shaft.

3. An operating mechanism for the movable element of a variableinductance device having straight-line movement, consisting of a rotaryshaft, a crank carried by said shaft, a lever pivotally connected at itsmid-portion with and carried by said crank, said crank having movementin opposite directions from a position in alignment with said lever, andmeans restraining movement of one end portion of said leversubstantially to the center line of said alignment, whereby movement ofthe other end portion of said lever is limited to substantiallystraight-line movement perpendicular to said center line of alignmentand said other end portion of said lever may be mounted for movement intheline of movement of the movable element of the inductance device foroperative connection with said movable element, said restraining meansincluding a member having a plane surface extending in the direction ofsaid center line of alignment, a roller carried by the restrained end ofsaid lever, and means holding said roller in engagement with said planesurface.

4. An operating mechanism for the movable element of a variableinductance device having straight-line movement, consisting of a rotaryshaft, a crank carried by said shaft, a lever pivotally connected at itsmid-portion with and 'carried by said crank, said crank having movementin opposite directions from a position in alignment with said lever, andmeans restraining movement of one end portionof said lever substantiallyto the center line of said alignment,-

whereby movement of the other end portion of said lever is limited tosubstantially straight-line movement perpendicular to said center lineof alignment and said other end portion of said lever may be mounted formovement in the line of movement of the movable element of theinductance device for operative connection with said movable element,said restraining means in-' cluding a membenhaving a plane surfaceextending in the direction of said center line of alignment, a rollercarried by the restrained end of said lever, and spring means holdingsaid roller in engagement with said plane surface.

5. An operating mechanism for the movable element of a variableinductance device having straight-line movement, consisting of a rotaryshaft, a crank carried by said shaft, a lever pivotally connected at itsmid-portionwith and carried by said crank, said crank having movement inopposite directions from a position in alignment with said lever, andmeans restraining movement of one end portion of said leversubstantially to the center line of said alignment, whereby movement ofthe other end portion of said lever is limited to substantiallystraight-line movement perpendicular to said center line of alignmentand said other end portion of said lever may be mounted for movement inthe line of movement of the movable element of the inductance device foroperative connection with said movable element, said restraining meansincluding a link pivotally connected at one end with said restrained endportion of said lever and extending in a direction substantiallyperpendicular to said center line of alignment, said link beingpivotally connected at its other end to a stationary support.

6. A permeability tuning operating mechanism for converting rotarymotion into substantially rectilinear motion, including a rotary drivingmember, a driven member having reciprocating movement, a lever attachedat one of its ends to said driven member and at its mid-portion directlyconnected with said driving member, and a bar pivotally connected at oneof its ends with the other end of said lever, the other end of said barhaving pivotal connection with a fixed support and restraining motion ofsaid other end of said lever to arcuate movement determined by said barwhereby motion of said first-mentioned end of said lever is restrainedto a substantially straight line extending perpendicularly to the lineof movement of said other end of said lever.

MARTIN J. KIRKi FREDERICK N. JACOB.

